The present invention relates to composite motion exercise machines in which both the actuating member and the user support move in a dependent relationship, and is particularly concerned with an exercise machine using a sliding linkage lifting system to displace the user support.
Exercise machines are divided into two major categories, single function and multi-function. A single function exercise machine performs one specific exercise to train a specific set of muscles. These machines are generally used in health clubs and gyms, where it is preferred for a user to perform one exercise on a specific machine for that exercise, and then to move on to another machine to perform a different exercise. Multi-function machines have different exercise stations for performing different exercises, using various muscle groups. Such machines are commonly used for in-home training, because of their space efficient design. Many types of single and multi-function machines have been designed in the past, most of which have a stationary seat or user support with an exercise arm or device linked to a load. Some have a stationary foot plate or actuating member and a movable user support.
Other, composite motion exercise machines are known in which both the actuating member and the user support move during exercise. In U.S. Pat. No. 5,330,405 of Habing et al., various exercise arms are attached to a movable user support sub-frame, which is connected to the main frame via a four bar linkage system. A lever arm is pivotally attached to the main frame and coupled through a cable and pulley system to the exercise arms and sub-frame. The lever arm has a movable carriage which bears against the lower links of the four bar linkage system. The load is supplied by the user's body weight, which can be increased or decreased by adjusting the position of the carriage along the lever arm and changing its contact point relative to the four bar linkage.
Other composite motion machines are described in U.S. Pat. No. 5,346,447 of Stearns, 5,733,229 of Dalebout et al., 5,928,116 of Chiang, and 6,015,369 of Rasmussen. U.S. Pat. Nos. 6,264,588 and 6,287,241 of Ellis describe a composite motion exercise machine comprising a main frame, slide rails attached to the main frame, an exercise arm pivotally secured to the main frame, a user engagement means attached to the exercise arm, a user support pivotally connected to the main frame, second slide rails attached to the user support, and a truck or slide linkage slidably engaged with the rails on the main frame and user support so that movement by the exercise arm moves the truck along the rails, forcing the user support to pivot and lift relative to the main frame. The load is attached to the user support. This requires two separate slide rails and linear bearings, increasing expense, and also requires a relatively long linear travel distance of the truck along the slide rails when the exercise arm is moved from the start to the ending position.